In many organisations, for example in industry, in large kitchens and in large hotels where many rooms need to be cleaned regularly, small containers, such as easily portable bottles, are frequently refilled with cleaning and sanitising liquids from bulk containers held at a filling station. The dispenser is typically of the type described in EP 0868137. This describes a manually operated dispenser for dispensing measured single shots of fluid from a reservoir into a container positioned beneath the outlet. The containers being filled are typically labelled or coloured, in order to indicate the liquid which they should contain. There are obvious risks of errors here, that a liquid might be filled into a container for which it was not intended, particularly when many people frequently visit a filling station. Simple colour coding systems, whilst helpful, do not remove the possibility of human error.
Attempts have been made to overcome this problem by electronic automated filling systems, but these tend to be very complex, involving for example the reading of bar code labels. Such systems are expensive, they require expert set-up and maintenance and are prone to the occurrence of faults.
Document US-B1-6,279,836 describes a fluid dispenser in which the insertion of containers for which the dispenser is not intended is prevented by providing inwardly facing projections on the sides of a container receiving portion of the dispenser which engage complementary grooves in the side of the container as it is inserted into the dispenser for filling. Once the container is inserted to its full horizontal depth, it can be raised whereby the projections follow a “T” arm of the groove in the container side. Raising the container brings the container mouth to a position where it surrounds a filling nozzle, and at the same time the container mouth raises a slider which operates the fluid dispenser main valve.